Delay firing mechanism



1962 M. E. EGGMAN 3,018,734

DELAY FIRING MECHANISM Filed Nov. 50, 1955 INVEN TOR. Mex f. Eswmm3,018,734 Patented Jan. 30, 1962 3,018,734 DELAY FG MECHANISM Max EarlEggman, Fort Wayne, Inch, assignor to The Magnavox Company, Fort Wayne,Ind, a corporation Filed Nov. 30, 1955, Ser. No. 549,919 6 Claims. ((31.10275) This invention relates generally to firing mechanisms forimpact-responsive projectiles and more particularly it relates to adelayed impact mechanism especially adapted for use in grenades, mortarshells, rockets, bombs, and the like.

Conventional firing mechanisms for grenades, mortar shells, and otherimpact-responsive projectiles are relatively complex and expensive andrequire close tolerances between parts. This is especially true where itis desired to provide delayed firing after actual impact of theprojectile with the target.

The principal object of this invention is to provide a simple andinexpensive firing mechanism for projectiles such as grenades, mortarshells, bombs, and the like, wherein there is delayed firing afterimpact with a target.

Another object of this invention is to provide a delayedimpact mechanismfor projectiles of various types which does not require spinning actionor setback of the firing mechanism at the time that the projectile islaunched or at the time that the projectile actually contacts itstarget.

Still another object of this invention is to provide a firing mechanismresponsive to impact with a target which will provide delayed detonationof a projectile.

In accordance with this invention there is provided a delayed impactfiring mechanism for grenades, mortar shells, bombs, or otherprojectiles comprising a sliding device having a detonator pin, meansnormally preventing said sliding device from moving the detonator pininto engagement with the detonator in response to impact, and a controlshaft which may be actuated to arm the mechanism by moving said slidingdevice into such a position that it is free to respond to the force ofimpact with a target to move the detonator pin into engagement with adetonator after a certain time-delay.

The full nature of the invention will be understoodfrom the accompanyingdrawings and the following description and claims:

FIG. 1 is a longitudinal cross section of a portion of a projectileincluding the firing mechanism as provided in accordance with thisinvention; and

FIG. 2 is a cross section taken on line 2-2 of FIG. 1.

Referring to the drawings, a portion of a projectile such as a handgrenade, mortar shell, or bomb is illustrated in FIG. 1, wherein thehand grenade or other projectile comprises a casing which may be theouter casing of the projectile or an inner casing adapted to house themechanism of the invention. Within casing 10 there is a cylindricalholder 11 for supporting an explosive charge 12. A primer 14 may benested within the charge 12 in conventional manner.

For detonating the primer 14, there is provided a slider 15 fitted insliding relation to casing 10 and including a striker wire or firing pin7 having a stabbing point thereon arranged in alignment with primer 14.A slider stop 17 may be arranged in the way of the slider 15 and securedto casing 10 by means of a pin 18 nested within stop member 17 andprojecting into the casing 10, as shown in FIG. 1. The stop member 17includes a slot 19 for receiving the slider lug 20 which projectsoutwardly on the main body portion of slider 15 and which supports thefiring pin 7. Lug 20 is illustrated in alignment with the slot 19,whereby the mechanism is in position to he fired in response to impactwith the target.

In order normally to prevent operation of the mechanism, slider 15 maybe mounted on a rotatable shaft 21 and keyed thereto by providing a keyslot 22 in shaft 21 and arranging the firing pin 7 to project into slot22. Shaft 21 is supported at one end within the end plate 23, attachedto casing 10 and at the other end in a locking disk 24 keyed as shown at24a on the end of shaft 21 and resting on stop member 17 for rotationwith respect thereto. Disk 24 includes a notch 25 which may normally bedisposed out of alignment with a locking pin 26 slidably mounted withinthe charge holder 11. The movement of locking pin 26 into notch 25 mayalso be used to release a rotor, shutter or other interrupting device inthe explosive train.

The slider 15 normally rests on the coil spring 28, one end of which maybe supported by end plate 23 and the other end of which engages andsupports the slider 15, as shown in FIG. 1.

When the projectile is initially manufactured and assembled, the shaft21 is rotated into such a position as to arrange the lug 20 out ofalignment with slot 19 in stop member 17. Also, the notch 25 in thelocking plate 24 is out of alignment with pin 26. This orientation ofparts prevents the slider 15 from moving the firing pin into engagementwith the primer 14. Thus, the grenade, mortar shell, or other projectileis disarmed and cannot be fired.

In order to arm the mechanism, shaft 21 may be rotated to such aposition that pin 26 may enter notch 25 and the lug 20 will be inalignment with the slot 19. This may be done manually before launchingor subsequent to launching by a clock mechanism or similar device. Withthe parts in this position, the grenade or mortar shell, or otherprojectile may be launched and the impact of the projectile with thetarget on the lower end thereof (FIG. 1) will cause the slider 15 tomove downwardly on shaft 21, compressing spring 28. Thus, the firingmechanism does not detonate primer 14 at the time of impact. Afterimpact, spring 28 expands to move slider 15 along the shaft 21 adistance suificient to engage firing pin 7 with the primer 14 thereby tocause detonation after a certain time period. This time period or delayis determined by such factors as velocity at the time of impact withlthetarget and target hardness. Thus, there may be some variation in timedelay as between different grenades or mortar shells or otherprojectiles.

From the foregoing description it will be apparent that the firingmechanism described herein is simple and inexpensive to manufacture.There are no parts which must be manufactured to close tolerances andthe assembly of parts requires only a simple manufacturing procedure.The invention provides a firing mechanism which normally may be disarmedand which may be easily armed prior to or subsequent to launching. Thus,there is adequate safety for handling and shipping. Also, the inventionprovides delay of detonation after impact with the target, whereby themechanism is especially adapted for hand grenades or other projectileswhere it is desired that the projectile bounce before exploding or whereit is desired that the projectile penetrate within the target beforeexplosion.

The invention claimed is:

1. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a locking pin slidably mounted in said holder, ashaft mounted in said casing in alignment with said primer and includinga locking disk mounted thereon adjacent said holder and having a notchnormally out of alignment with said locking pin and movable intoalignment therewith when said shaft is rotated to a certain position, alongitudinal slot in said shaft aligned with said primer, a slidermovably mounted on said shaft and having a spacing lug projectingtherefrom toward said locking plate, a firing pin mounted in said lugand projecting into said shaft slot and toward said primer, a stopmember fixed to said casing between said locking plate and said sliderand normally engaging said lug to prevent contact between said firingpin and said primer, said stop member including a slot disposed in aposition to receive said lug when said shaft is rotated to align thenotch in the locking disk with said locking pin, thereby to permitmovement of said firing pin into stabbing contact with said primer, andspring means disposed between the front end of said casing and saidslider for permitting spring compressional movement of said slider inresponse to impact of said casing with a target and delayed returnmovement of said slider and therewith said firing pin into stabbingengagement with said primer.

2. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a shaft mounted in said casing in alignment withsaid primer, a locking mechanism operatively associated with said holderand said shaft for determining an arming position of said shaft, alongitudinal slot in said shaft aligned with said primer, a slidermovably mounted on said shaft and having a spacing lug projectingtherefrom, a firing pin mounted in said lug and projecting into saidshaft slot and toward said primer, a stop member fixed to said casingadjacent to said lug and normally engaging said lug to prevent contactbetween said firing pin and said primer, said stop member including aslot disposed in a position to receive said lug when said shaft isrotated to said arming position, thereby to permit movement of saidfiring pin into stabbing contact with said primer, and spring meansdisposed between the front end of said casing and said slider forpermitting spring compressional movement of said slider in response toimpact of said casing with a target and delayed return movement of saidslider and therewith said firing pin into stabbing engagement with saidprimer.

3. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a locking pin slidably mounted in said holder, ashaft mounted in said casing in alignment with said detonator andincluding a locking disk mounted thereon adjacent said holder and havinga notch normally out of alignment with said locking pin and movable intoalignment therewith when said shaft is rotated to a certain position, alongitudinal slot in said shaft aligned with said primer, a slidermovably mounted on said shaft, a firing pin mounted in said slider andprojecting into said shaft slot and toward said primer, means normallyeffective to prevent contact between said firing pin and said primerexcept when said shaft is rotated to said arming position, thereby topermit movement of said firing pin into stabbing contact with saidprimer, and spring means disposed between the front end of said casingand said slider for permitting spring compressional movement of saidslider in response to impact of said casing with a target and delayedreturn movement of said slider and therewith said firing pin intostabbing engagement with said primer.

4. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a shaft mounted in said casing in alignment withsaid primer, a locking mechanism operatively associated with said holderand said shaft for determining an arming position of said shaft, alongitudinal slot in said shaft aligned with said primer, a slidermovably mounted on said shaft, a firing pin mounted in said slider andprojecting into said shaft slot and toward said primer, means normallyeffective to prevent contact between said firing pin and said primerexcept when said shaft is rotated to said arming position, thereby topermit movement of said firing pin into stabbing contact with saidprimer, and spring means disposed between the front end of said casingand said slider for permitting spring compressional movement of saidslider in response to impact of said casing with a target and delayedreturn movement of said slider and therewith said firing pin intostabbing engagement with said primer.

5. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a shaft mounted in said casing, a slider movablymounted on said shaft, a firing pin mounted in said slider andprojecting toward said primer, means normally effective to preventcontact between said firing pin and said primer except when said Shaftis rotated to an arming position, thereby to permit movement of saidfiring pin into stabbing contact with said primer, and spring meansdisposed between the front end of said casing and said slider forpermitting spring compressional movement of said slider in response toimpact of said casing with a target and delayed return movement of saidslider and therewith said firing pin into stabbing engagement with saidprimer.

6. A delayed impact firing mechanism comprising a casing, an explosivecharge holder in the rear end of said casing for holding an explosivecharge and a primer, a slider movably mounted in said casing, a firingpin mounted in said slider and projecting toward said primer, meansnormally effective to prevent contact between said firing pin and saidprimer except when said slider is rotated to an arming position, therebyto permit movement of said firing pin into stabbing contact with saidprimer, means operable externally of said firing mech- -anism forrotating said slider to an armed position, and

spring means disposed between the front end of said casing and saidslider for permitting spring compressional movement of said slider inresponse to impact of said casing with a target and delayed returnmovement of said slider and therewith said firing pin into stabbingengagement with said primer,

References Cited in the file of this patent UNITED STATES PATENTS1,313,930 Taylor Aug. 26, 1919 1,916,244 Woodberry July 4, 19332,595,757 Brandt May 6, 1952

